Letters will be sent over the next three weeks to householders who have had solid wall insulation installed through the Energy Company Obligation (ECO4) scheme or the Great British Insulation Scheme (GBIS), Miatta Fahnbulleh MP announced in the House of Commons on 23 January 20251.
The announcement follows a deep dive by TrustMark into work carried out and lodged since ECO4 began, which brought to the Government's attention that the failure rate for these installations across the industry is higher than expected across certification bodies1. ECO4 launched in July 2022, and both schemes were designed to support households on the lowest incomes with funding for energy efficiency measures1. Funding for solid wall insulation, external wall insulation (EWI) and internal wall insulation (IWI) has been available to householders meeting the scheme criteria who live in solid wall properties1.
Ofgem has been tasked with managing the phased mailout and is setting up a call centre and a website to help manage householder enquiries1. The Installation Assurance Authority (IAA), an independent certification body, said it has been notified of a very small number of failures associated with its certification activities, and that these were markedly lower than failure rates associated with some other certification bodies1.
"Today, Miatta Fahnbulleh MP announced in the House of Commons that over the next three weeks, letters will be sent to householders, who have had solid wall insulation installed to their homes through these schemes."
The IAA said it is the first certification body to put an action plan in place to carry out a deep dive into the issues raised, and that it has identified some concerns which will be addressed by certified installers or by the IAA guarantee where one is in place1. It said it remains confident about the overall quality of work registered under the scheme1. The Government has released guidance for householders setting out who may be affected and what the next steps are1. The IAA said householders who had solid wall insulation installed through ECO4 since July 2022 or through GBIS can be assured their measure is likely functioning as it should1.
| Item | Detail |
|---|---|
| Schemes covered | ECO4 (from July 2022) and GBIS1 |
| Measures concerned | Solid wall insulation, external wall insulation, internal wall insulation1 |
| Mailout period | Over the next three weeks from 23 January 20251 |
| Managed by | Ofgem, with a call centre and website1 |
Why it matters for households
Solid wall insulation is one of the more consequential measures a home can take on, because solid walls lose heat readily and the work is difficult and costly to put right if it goes wrong. For a household that has had solid wall insulation fitted under ECO4 or the Great British Insulation Scheme, the letter is a route to finding out whether the installation meets the standard expected, and to a remedy where it does not. Poorly installed insulation can leave a home no warmer than before, and in some cases can affect the wall itself, so the practical value of the exercise lies in identifying defective work while guarantees and installer obligations still apply. The announcement does not change eligibility for either scheme, and no new funding has been reported. For homes still considering insulation and glazing as a route to lower bills and less reliance on imported gas, the episode is a reminder that the quality of the installation, not only the measure chosen, determines the result. Householders who receive a letter and are unsure whether it is genuine can check how Ofgem letters about insulation are verified.
What happens next
The phased mailout runs over the three weeks from 23 January 2025, managed by Ofgem, which is setting up a call centre and a website for enquiries1. The Government's householder guidance sets out who may be affected and the next steps1. The IAA said householders with concerns about work completed by an IAA registered installer can use its enquiry form1. No further dates have been reported.